South Africa’s ruling party is at risk of further splits amid a battle for senior positions in the ANC, deputy secretary-general Jessie Duarte said.

There is intense jostling to replace President Jacob Zuma, 74, as the head of the party and for other top positions, despite rules forbidding active campaigning, Duarte, 63, said in an interview in Johannesburg.

The concern is that the losing group could break away to form a new party, as has happened in the lead up to or after previous ANC elective conferences, she said.

The ANC’s leadership contest comes at a time when the party risks losing the majority it’s held in every vote since the first multi-racial ballot in 1994.

A split could drag its support down to below 50% in the 2019 national elections, giving an opportunity for the opposition to join forces to take power.

Deputy President Cyril Ramaphosa, 64, and Nkosazana Dlamini-Zuma, 68, a former African Union chairwoman and the president’s ex-wife, are seen by analysts as the main contenders to lead the ANC.

“Since 2007, every ANC conference has led to one or other split,” Duarte said. There could be “a spoilers’ breakaway after this conference”, she said.

Two major breakaway groups have cut into the ANC support base over the past decade. Some members who supported Thabo Mbeki at the 2007 conference formed the Congress of the People after Zuma took control of the party, while Julius Malema, its youth wing leader, formed the Economic Freedom Fighters after being expelled from the ANC in 2012.

While Cope’s backing has dwindled, the EFF garnered about 8% of the vote in local government elections last year. That helped slash the ruling party’s national support to 54%, its worst-ever electoral performance, and for opposition parties to take control of the capital, Pretoria, and the economic hub, Johannesburg.

The ANC needs to manage the electoral contest better and should consider allowing a limited time for candidates to campaign, Duarte said. Proposals such as introducing an electoral college to handle the internal vote will be discussed at a policy meeting in June, she said.

While rules still prohibit campaigning, groups continue to push for their candidates for the December election.

“People are lobbying, there’s no doubt,” Duarte said. “Lobby groups are all over the country, big ones, small ones, bold ones, all of that is happening.”

The ANC’s women’s league has publicly backed Dlamini-Zuma to succeed Zuma, while trade union federation Cosatu and Jackson Mthembu, the party’s parliamentary chief whip, have said they support Ramaphosa.

Other leaders expected to contest the race for the top positions include treasurer-general Zweli Mkhize and Baleka Mbete, the speaker of parliament and ANC chairwoman.

The frontrunner to replace Zuma will probably only become clear in the second half of the year, Duarte said.